How to tell if a tree is dangerous

A number of factors need to be taken into consideration when assessing a tree.
Some of these questions will require knowledge of the trees history, so it can be helpful to think
about them before you meet with an Arborist. If you have only lived at the property for a short
amount of time, consider talking with neighbours or the previous owner of the property.
An Arborist will need to consider;

  • What species is the tree, and how well suited is it to the growing conditions?
  • Are there any structural defects in the crown, and if so how significant are they?
  • Are there any sections of the tree that have been compromised by previous poor pruning, pest and disease attack, mechanical damage or any other notable problems?
  • Does the tree have a history of limb failure/s, and if so what size were they, how often have they occurred, and where in the crown did they come from?
  • What will need to be considered if the arborist identifies a structural defect or other issues?
  • What is the area under the tree or defect used for, and how often is it occupied.
  • Are there any structures threatened by the defect?
  • How large is the affected limb/s and how likely is it to fail.

Once the problems are established, we can start to think about mitigation options.

  • First we need to know what the legal status of the tree is ie; Regulated, Significant, or does the Native vegetation act apply?
  • Can we mitigate the issues through reduction pruning, limb removal, or a combination of the
  • Can we simply move the target ie; move a trampoline or play structure, out from under the
  • Do you need to do anything to the tree at all, even though it may have major defects? If the tree is not over an area that is used very often (garden beds, paddock, shed, etc.), does it matter if a limb falls off?
  • Would the cost of pruning be more than the cost of potential damage?
  • Finally, if no management options are suitable. Does the tree need to be removed?